'Solid performance'

Mrs Griffiths thanked everyone concerned for "their hard work over the last year which has brought about this excellent result".

At best the Welsh Labour government's claims of a 'remarkable achievement' are misleading. At worst they are completely falseAndrew RT Davies, Conservative assembly leader

She added: "A solid financial performance has put NHS Wales in the strongest possible position to deliver the improvements, efficiencies and changes which will underpin its success into the future."

The news comes as health boards prepare to publish blueprints for how they will deliver services in future.

Ministers have thrown their weight behind a report setting out the benefits for centralising some services.

But they insist district general hospitals will not close or be downgraded as part of the shake-up.

Conservative opposition leader Andrew RT Davies said: "At best the Welsh Labour government's claims of a 'remarkable achievement' are misleading. At worst they are completely false."

Plaid Cymru finance spokesman Ieuan Wyn Jones said: "This is an astounding attempt by the Labour Welsh government to mislead us into thinking that our LHBs have stayed within budget."

Welsh Liberal Democrat leader Kirsty Williams said: "I am absolutely flabbergasted that the health minister can call this a 'remarkable achievement'. What's remarkable is that the health minister thinks that this is an achievement."

The Welsh NHS Confederation, which represents LHBs, said £290m had been saved in 2010/11 without harming services.

Its director, Helen Birtwhistle, said: "Although the financial environment is undoubtedly a factor in the need to make radical change, many of the changes would need to be made anyway to make necessary improvements to the quality of our services."